Tuning mechanism for a string musical instrument



June 8, 1965 N. P. ULRICH 3,187,617

TUNING MECHANISM FOR A STRING MUSICAL INSTRUMENT Filed Aug. 27, 1963 796/ Figi.

62 /-v- /A/VE/vTo/P 84 sa Nam/AL A? ULP/CH 6., ATTORNEY United StatesPatent O M 3,187,617 TUNING MECHANISM FR A STRING MUSICAL INSTRUMENTNorval P. Ulrich, 1203 Carrie, Des Moines 9, Iowa Filed Aug. 27, 1%3,Ser. No. 304,996 9 Claims. (Cl. 34-312) This invention relates generallyto string musical instruments, and more particularly to such instrumentsas the guitar, mandolin, banjo and the like, although not limitedthereto, which are played by picking or stroking the strings.

An object of this invention is to provide a stringed instrument on whichone or more or several chords can be played Without resort to difficultfingering operations which can otherwise be performed only by skilledperformers thus making it possible for players having only rudimentaryskill to give performances comparable to the performances of players ofsuch greater experience and accomplishment.

To the above end, the stringed instrument disclosed herein is providedwith a mechanism for each string which may be remotely actuated, as bymovement of the players foot, to automatically vary the tension of thestring a predetermined amount. By providing each string of theinstrument with such a mechanism, whereby the tension of each string maybe varied to any one of several quantities when several strings arestroked a definite pre-determined chord is produced. Thus, no particularmusical skill is required to play any chord the instrument has beenpreviously set to produce.

The inventon contemplates the addition to an otherwise more or lessconventional stringed instrument of a mechanism for each string, and ofa plurality of foot operated electric switches for each mechanism,whereby actuation of any one switch results in the mechanism operatingto elfect a predetermined degree of tension on the string.

It is, therefore, an object of this invention to provide an improvedautomatic chord tuning mechanism for a string musical instrument.

It is another object of this invention to provide a chord tuningmechanism having a structure automatically responsive to remotelyoperable means for varying the tension of a string from one degree to apredetermined one ofvseveral other degrees of tension.

Yet another object of this invention is to provide a chord tuningmechanism for selectively varying the tension of all or any combinationof strings of a string instrument so that certain strings are tightenedwhile others are slackened, all in response to a single operation of acommon actuating member, such as, for example, a foot pedal.

Still another object of this invention is to provide a chord tuningmechanism for each string of a string instrument wherein a rocker arm isoperable to vary the tension on a string in response to movement of ashaft, the shaft automatically started and stopped as to its movementdue to electric coaction of a pair of solenoids and a plurality ofelectric switches selectively engageable by said shaft.

It is another object of this invention to provide a chord tuningmechanism for a string instrument capable of attaining said abovementioned objects, and which is economical to manufacture, effective inoperation, and easily serviced.

These objects, and other features and advantages of this invention willbecome readily apparent from the the following description when takeninto consideration with the accompanying drawings, wherein:

FIG. l is a side elevational View of a schematic nature of the chordtuning mechanism of this invention, in assembled relation for onestring;

3,187,617 Patented June 8, 1965 JCe FIG. 2 is a View similar to FIG. lshowing the mechanism in a different position Wherin the tension of thestring is varied over FIG. 1;

FIGS. 3, 4, and 5 are enlarged side elevational views of one electricswitch in three different positions due to coaction with a switch block;and

FIG. 6 is a diagrammatic view of the electric circuit for the singlestring, chord tuning mechanism of FIG. 1.

Referring now to the drawings, a fragment of a single musical string 10is shown in FIGS. 1 and 2. The string 1i) is but one of several strings,six for example of a conventional stringed instrument having a soundingboard supported by legs or the like at ya predetermined height above afloor. The strings 10 are stretched lengthwise of the sounding board inan overlying manner due to a pair of bridges secured to the board inlongitudinal spaced relation. Each string 10 is attached at one end to atuning key of a type ordinarily provided on guitars and other similarlystringed instruments. The string 10 is thus tuned in a conventionalmanner by turning the tuning key.

With this conventional arrangement in mind, applicants apparatus forautomatically varying the degree of tension on the string 10 along or incombination with other strings is indicated generally at 11 in FIGS. land 2. The string 10 is connected, at the end opposite the tuning key,to the upper end 12 of a tension adjusting bar 13. A notch 14 is formedin one side of the upper end 12 for receiving the pointed end of astationary fulcrum 16 about which the adjusting bar 13 is adapted torock. A spring 17 is secured between the upper end 12 and a bolt 18threaded through a nut 19 and a stationary plate 21 for providing afine, Vernier-type adjustment on the string 1t) via the adjusting -barupper end 12.

Integral with the upper end 12 of the adjustment bar 13, a lower end 22depends angularly away therefrom and is provided with a nylon wheel 23rotatably mounted at the extreme end thereof. The wheel 23 is engageablewith any one of a plurality, four for example, of tuning adjustmentknobs 24, 25, 26 and 27 which are threadably inserted through anelongated shaft 28 in longitudinal spaced relation. It is readilyobserved that the adjustment knobs protrude at varying extent, wherebyupon engagement of the wheel 23 with one knob 27, for example, thetension on the string 1li is considerably less than the tension thereonwhen the wheel 23 is engaging the knob 24 furthest from knob 27.

The adjustment knobs are secured to the shaft 28 intermediate a pair ofseparators 29 and 31 through which the shaft extends for reciprocationbetween two pairs 32 and 33 of guides which extend at right angles tothe longitudinal axis of the shaft 28. At the left end 34 of the shaft28, as viewed in FIG. 1, are a pair of parallel arms 36 and 37 each ofwhich is independently and pivotally connected to the shaft end 34. Acompression spring 38 is inserted between the arms 36 and 37 to maintainthem in a spaced apart condition. A pair of limit pins 39 and 41 limitthe placement of the arms 36 and 37.

In their normal condition, the arms 36 and 37 straddle in a non-engagingmanner a drive member 42 which, when operating, rotates continually inthe direction indicated by the arr-ow in FIG. l. To selectively moveeither arm 36 or 37 into engagement with the drive member 42, a pairofrsingle-acting solenoids 43 and 44 are provided on opposite sides ofthe drive member 42 and on the outer sides of the arms 36 and 37. Therespective plungers 46 and 47 of the solenoids are continually engagedwith the arms 36 and 37, respectively. j

As illustrated in FIG. l, when the upper solenoid 43 is momentarilyenergized in a manner hereinafter described, the plunger 46 of thesolenoid 43 is extended to force the arm 36 into engagement with thedrive member 42. Rotation of the drive member 42 thus moves the arm 36to the right as viewed in FIG. 1 which results in movement of the shaft28 to the right. Should, conversely and subsequently to energization ofthe upper solenoid 43, the lower solenoid 44 be momentarily energized,its plunger 47 is extended to move the lower arm 37 into engagement withthe drive member 42 (FIG. 2). Rotation of the drive member 42 in thedirection indicated would therefore move the arm 37 to the left, whichwould result in movement of the reciprocal shaft 28 to the left, asviewed in FIG. 2.

At the right end 48 (FIG. 1) of the shaft 28, a control block 49 isprovided which has a quartet of control faces S1, 52, 53 and 54 o neface being formed at each corner of the rectangular block 49.Intermediate the inner and outer upper faces S1 and 52, a flap topsurface 56 is provided, whereas a flat bottom surfacer57 is provided onthe control block 49 between the inner and outer lower faces 53 and 54;Disposed about the control block 49 in longitudinally spaced relationare a pair of normally closed electric switches 58 and 59 of the twoleaf type and disposed above and below the c-ontrol block 49 are a pairof three-leaf electric switches 6l and 62.

Referring nowA to the electric circuit for the chord tuning mechanism inFIG; 6, it is seen that the solenoids 43 and 44 are connectedby a line63 to one side of a leaf switch 58, where the current is then conductedthrough lines 94 and '79 to the lower solenoid 44. The solenoid 44 isenergized to extend the plunger 4'7 whereupon the arm 37 (FIG. 2) ismoved into engagement with thev rotating drive member 42. Clockwiserotation by the member 42 thus pulls the arm 37 to the left in FIG. 2,also responsively moving the shaft 28 to the left.

As the various faces and surfaces of the control block 49 engage withand disengage from the movable leafs 84 and 77 of the switches 62 and6I, respectively, the circuit is not affected due to the respectivefoot-operated switches 67 and k68 therefore being open. However, duringthe movement of the shaft 28 to the left from its FIG. 2 position, theinnerV face 51 of the control block 49 eventually engages the movableleaf 92 (FIGS. 1 and 6) of the switch 58 and breaksits contact `with'theleaf 93. This'operation thus opensv the circuit to the solenoid 44,whereupon thesolenoid 44 is de-energized' and the plunger 47 retracted.`Thesprin'g 38 is operable to immediately move the arm 37 away from the'drive member v42, and the shaft 28 is stopped with the knob 2'7 engagingthe' wheel 23, the rocker bar 13 accordingly pivoted Y counter-clockwiseabout the fulcrum 16, thus tightening source of electric current, withthe other side of the source connected by a line64 to a plurality, fourfor example, of normally open, ori-off switches 66, 67,' 68 and 69arranged in parallel. Although not shown herein, it may readily berealized that these switches 66-69 are manually operable, as by theplayers foot. The switch 69 is interconnected by a line Il to a movableleaf 72 ofthe switch 59 with the stationary leaf 73 connected by` a line74 to the upper solenoid 43. The switch 68 is connected by a line 76 tothe center movable Vleaf 77 of' the switch 6I, which is normally closedagainst a stationary leaf 78 conected in turn by a line 79 to the lowersolenoid 44. The upper stationary leaf 8l of the switchfol is-connectedvia lines 82 and 74 tothe upper solenoid 43.

Switch 67 is connectedby a line 83 to the center movable leaf 84 of thelower switch 62, which leaf 84 is normally closed against the upperstationary leaf 86, connected in turn via lines 8'7 and 79 to the lowersolenoid 44; The lower stationary leaf 88 is connected by a line 89 andthe line 74 to the upper solenoid 43. `The left-most switch 66 isconnected, when closed, by a line 91 to the movable leaf 92 of theswitch 58, with the stationary leaf 93 connectedby lines 94 and79 to thelower solenoid 44.

In operation of the chord tuning mechanismv Il, assume that neithersolenoid 43 and 44 isenergized, wherefore neither arm 36 and 37 engagesthe driven member 42, that the shaft 23 is in the position of FIG. 2,and that the player of the instrument desires to change the tension onthe string 10 to a degree accomplished by engaging the wheel 23 withthetuning adjustment Vknob 27.

Itshould bevmentioned herein that the circuitry and structure ofapplicants chord tuning mechanism, as

demonstrated hereinafter, is such that upon closing the manuallyoperated switch 66, the shaft 28 will move to engage the wheel 23withthe knob 27; upon closing the switch 67, the shaft willresponsivelymove to engage the wheel 23 with the knob 26; upon closing the switchd8, the shaft 28-will be moved to place the knobk 25 in engagement withthe wheel 23; and upon momentarily closing the switch 69, energizationofl one ofthe solenoids will result in the drive member 42 moving theshaft 28 until the circuit is opened-by operation of the switch 59,whereupon the movement of the shaft 28 stops with the Y Vknob 27engaging the wheel 24.

the string It).

Should it'be desirable to slaken the tension on the string It) slightly,for' example to change the position of the bar I3 to one of engagementwith the knob 25, the switch 68 is closed. Current is then-conductedthrough the line 83 to the center, movable leaf '7'7 of theV switch 61.As illustrated in FIGS. land3 the leaf 7'7', engaged withr the uppersurface 56 of theV control yblock 49, is in contacting engagement withthe upper leaf 81 (FIG. 6) of the switch.'

Current is therefor conducted through line 74 to the upper solenoid 43.l

Energization of solenoid 43 extends the plunger 46 whereupon the arm 36is moved into engagement with the drive member 424. The counterclockwise movement of the member 42 Vforces the shaft 28 to the right inFIG. l. Referring to FIG. 4, it is seen that when the leaf 77 engagesthe inner face 51 of the control block 49, the leaf 77 moves away fromcontacting engagement with the upper leafV 81. The circuit to thesolenoid 43 is therefore broken, the plunger 46 retracted, and with thearm 36 disengaged from the member 42, the shaft 28 is stopped with thetension adjustment bar 13 repositioned, being engaged at the wheel 23 bythe tuning adjustment knob'25. It is therefore clearly seen that a chordtuning mechanism is provided for a string instrument wherein one or morestrings are automatically adjustable as to their tension, either singlyor in combination, by the coaction between a set of shaft-operatedelectric switches, a shaft, and a pair of solenoidsresponsibe to one ormore of the switches. It is readily seen that the switch 66, forexample, could be mechanically or electrically connected with a similarswitchof another set of switches for another string, lall similar to thestructure Il. Then, upon closing switch 66 to effectv a variance in thetension of the string lll another or several other strings of the singleinstrument associated with string Slt) could also have their tensionaffected, thereby effecting a new, predeterminedl chord without thelingers of the players hand beingl placed on the strings.

I claim: I. In a musical instrument having one or more tensioned stringsdisposed for audible vibration, means for progressively and'selectivelyvarying the tensionof each string comprising in combination;

rocker means connected at one end to a string and operable upon beingrocked to vary the tension on said string; Y Y reciprocable meansoperatively connected to said rocker means and effective to rock saidrocker means in response to reciprocation; and i manually controlledelectric means for selectively reciprocating said reciprocable means.

2. In a musical instrument having one or more tensioned strings disposedfor audible vibration, means for progressively and selectively varyingthe tension of each string comprising in combination:

rocker means connected at one end to a string and operable upon beingrocked to vary the tension on said string;

reciprocable means operatively connected to said rocker means andeffective to rock said rocker means in response to reciprocation;

drive means operable upon engagement to reciprocate said reciprocalmeans in a predetermined direction; and

manually controlled electric means for selectively operating said drivemeans.

3. In a musical instrument having one or more tensioned strings disposedfor audible vibration, means for progressively and selectively varyingthe tension of each string comprising in combination:

rocker means connected at one end to a string and operable upon beingrocked to vary the tension on said string;

reciprocal means operatively connected to said rocker means andeffective to rock said rocker means in response to reciprocation;

a pair of arms independently connected to said reciprocal means; drivemeans operable upon engagement by one of said arms to move saidreciprocal means in one direction, and operable upon engagement by theother one of said arms to move said reciprocal means in an oppositedirection; and

manually controlled electric means operatively engageable with said armsforselectively moving one arm into engagement with said drive means.

4. In a musical instrument having one or more tentioned strings disposedfor audible vibration, means for progressively and selectively varyingthe tension of each string comprising in combination:

rocker means connected at one end to a string and operable upon beingrocked to vary the tension on said string;

reciprocal means operatively connected to said rocker means andeifective to rock said rocker means in response to reciprocation;

an electric circuit;

electromagnetic means interposed in said circuit and operable to effectreciprocation of said reciprocal means;

switch means interposed in said circuit and operable by engagement withsaid reciprocal means, said electromagnetic means activated in responseto operation of said switch means; and

manually controlled electric means interposed in said circuit foreffecting activation through said switch means of said electromagneticmeans.

5. In a musical instrument having one or more tensioned strings disposedfor audible vibration, means for progressively and selectively varyingthe tension of each string comprising in combination:

rocker means connected at one end to a string and operable upon beingrocked to vary the tension on said string;

reciprocal means operatively connected to said rocker means andeffective to rock said rocker means in response to reciprocation;

drive means adapted upon engagement with said reciprocal means to effectreciprocation thereofam an electric circuit; I

electromagnetic means interposed in said circuit and engageable withsaid reciprocal means for effecting engagement thereof with said drivemeans;

switch means interposed in said circuit and having a normal firstposition, said switch means engageable by said reciprocal means andhaving a second position, said electromagnetic means responsive to saidchanges of position to effect movement of said reciprocal means; and

manually controlled electric means interposed in said circuit foreffecting activation through said switch means of said electromagneticmeans.

6. In a musical instrument having one or more tensioned strings disposedfor audible vibration, means for progressively and selectively varyingthe tension of each string comprising in combination:

an electric circuit;

a manually operated normally open switch interposed in said circuit;

a rocker arm connected at one end to a string and operable upon beingrocked to vary the tension on said string;

reciprocal means operably connected to said rocker arm and effective torock said rocker arm in response to reciprocation;

drive means adapted upon engagement with said reciprocal means toreciprocate said reciprocal means in a predetermined direction;

electromagnetic means interposed in said circuit for moving saidreciprocal means into and out of engagement with said drive means; and

switch means engageable by said reciprocal means for transmittingcurrent from said switch to said electromagnetic means for effectingsaid reciprocal means movement.

7. In a musical instrument having one or more tensioned strings disposedfor audible vibration, means for progressively and selectively varyingthe tension of each string comprising in combination:

a rocker arm connected at one end to a string and operable upon beingrocked to vary the tension on said string;

a shaft operably connected to said rocker arm and effective to rock saidrocker arm upon reciprocation of said shaft;

drive means engageable with said shaft to effect reciprocation thereofin either of opposite directions;

an electric circuit;

electromagnetic means interposed in said circuit and operable uponactivation to move said drive means and said shaft into engagement witheach other;

at least a pair of switches interposed in said circuit and having normalfirst positions, each of said switches selectively engageable with saidshaft and thereby operable to attain respective second positions, eachof said switches independently connected with said electromagnetic meansand operable to activate said electromagnetic means.

`8. In a musical instrument having one or more tensioned `stringsdisposed for audible vibration, means vfor progressively and selectivelyvarying the ten-sion of each string comprising in combination:

rocker means connected at one end to a string and operable upon 'beingrocked to vary the tension on said string;

reciprocal means operatively connected to said rocker means andeffective to rock said rocker means in response to reciprocationthereof, said reciprocal means including a shaft having a switch blockat one end thereof;

drive means `en-gageable with said shaft to elfect reciprocation of saidreciprocal means in either of opposite directions;

an electric current;

electromagnetic means interposed in said circuit and energizable toeffect selective engagement of said drive means and said shaft toprovide movement of said reciprocal means in a predetermined direction;

1. IN A MUSICAL INSTRUMENT HAVING ONE OR MORE TENSIONED STRINGS DISPOSEDFOR AUDIBLE VIBRATION, MEANS FOR PROGRESSIVELY AND SELECTIVELY VARYINGTHE TENSION OF EACH STRING COMPRISING IN COMBINATION: ROCKER MEANSCONNECTED AT ONE END TO A STRING AND OPERABLE UPON BEING ROCKED TO VARYTHE TENSION ON SAID STRING; RECIPROCABLE MEANS OPERATIVELY CONNECTED TOSAID ROCKER MEANS AND EFFECTIVE TO ROCK SAID ROCKER MEANS IN RESPONSE TORECIPROCATION; AND MANUALLY CONTROLLED ELECTRIC MEANS FOR SELECTIVELYRECIPROCATING SAID RECIPROCABLE MEANS.